Apparatus for generating high-frequency electric currents



A.HEYLAND. I APPARATUS FOR GENERATING HIGH FREQUENCY ELECTRIC CURREN'I'S.

. APPLICATION FILED IULYZB, I914- 1,417,9 1 3, Patented May 30, 1922.

UNITED STATES PATENT OFFICE} ALEXANDER HEYLAND, OF BRUSSELS, BELGIUM.

APPARATUS FOR GENERATING HIGH-FREQUENCY ELECTRIC CURRENTS.

Application filed July 28,

To all who m it may concern Be it known that I, ALEXANDER IIEYLAND, engineer, subject or". the G erman Empire,'residing at Brussels, Belgium, have invented certain new and useful Improvements in Ap paratus for Generating High-Frequency Electric Currents, of which the following is a specification.

My invention relates to theproduction of high frequency electric currents by machines in which the frequency is not determined by the number of poles, or the pitch thereof, and the circumferential. speed, but by oscillations or pulsations in the field circuits of the machine.

According to my invention, in a machine having, for example, fixed magnets, the gaps between the successive poles of opposite polarity are bridged across the rotor surface by magnetic fluxes in different phases.

The apparatus employed for this purpose is characterised externally by the fact that the active stator and rotor surfaces are ditferently subdivided in the direction of their movement, and that the iron surface of the rotor forms segments which bridge the between the pole tips successively under different phases.

lVith the known methods of producing oscillations by means of a rotor differing, in its division, from the pole distribution, pointed ortoothed poles and a toothed rotor are always employed to produce a pulsating variation of the magnetic resistance to the flux entering the rotor radially.

Machines of this type have various drawbacks. In the first instance the oscillations yithin the iron of the rotor are powerfully damped, even if the rotor is well divided, and.

in this respect the machines are even inferior to unipolar machines having toothed rotors. Secondly, as is the casewith unipolar machines, with closely arranged teeth the comb-like distribution of the field is apt to be blurred, and only very weak oscillations are produced. Thirdly, this principle does not allow of any closed windings being placed on the rotor for producing counter ampere turns, since these turns would have a damping effect on the oscillations, so that machines of this type are only capable of very limited outputs. I

' According to my invention the act1ve rotor iron is disposed solely at the surface of the rotor and always in that segment which bridges the slot separating the pole tips of two stator poles, the segments underneath 1914. Serial no 853,766.

the stator poles being inactive. The stator field is closed tangentially over the corresponding rotor segments. g

It will be seen from this that my arrangement not only obtains the'advantage of the Specification of Iletters Patent. Patented May 30, 1922. l

ed by the closed windings and also by the fact that the crosssection of the active segments is reduced at a small distance beneath the surface. Also, I do not obtain the objectionable blurring of the field, but a sharp change .whenever the edge of an active rotor segment passes from beneath a pole tip, since the magnetic lines are prevented from establishing a new path for themselves "from one segment to the other due also to the closed winding. s

The open gaps may be filled with copper or any other electric conducting metal or with windings or bars which may be connected in any manner to each other or in themselves. The counter ampere turns produced in the same increase the pulsations on the one hand and on the other hand increase the torque and efficiency of the ma chine when under load.

The invention is diagrammatically illustrated in the accompanying drawings, in which,-

Figs, 1, 1 2, 9 3, 4t and, 4" show some arrangements by way of example.

In the drawings sections of the stator and rotor are shown-developed in a straight line, for the sake of cloarness, and the separate figures showing different arrangements as follows: i

i Figure 1 a diagrammatic view showing the stator poles of equal size and the rotor segments also of equal size and'of comparatively large number compared with the number of stator poles, there being only one winding on-the stator poles serving to carry both the exciting current and the useful current.

Figure 2 is the stator poles divided into alternately arranged groups of different sizes, the larger poles carrying an induced winding andthe smaller poles carrying an excitlng winding,

a diagrammatic view showing while the active rotor segments are equal in 7 size and approximately the same as the coils are all wound in the same direction on their respective poles in order that the 111- duced poles may he all the same, the arrangement being such that the flux in one induced pole always increases as the tluxjn the next induced pole is decreasing; the indueed windings consequently being wound in opposite directions in order that the impulses may add.

F ig. 3 a diagrammatic view somewhat similar to Fig. the sire of the rotor segments and ot the smaller stator pole tips being, however, reduced as compared to the sine oil? the large stator pole tips. with the result that the induced poles are some of one polarity and some o'l? another the excitin; coils are connected differently.

Figure 4 is a diagrammatic view some what similar to Figure 3, hut showing the stator projection all of the same size and the active rotor segments relatively large as compared with the stator projections.

In Figure 1, S designates the stator, and R the rotor.

The poles of the stator are designated by successive numerals 1. Q, 3. l. 5 and the stator coils are in series and so connected that a current :ted to the terminals a a produces N and S poles. The rotor has teeth 5, b, I), the pitch of which is in this example of the pole pitchof the stator. In the position shown the flux passing :liroxn pole 3 to the two poles 2 and 4, traverses the surface of the two teeth 7), 7), which magnetically bridge the slots which they face. ljli now the rotor is considered as having turned Q; the rotor pitch from the position of Fig. 1, a rotor slot will he opposite a stator slot, so that the hridginc is interrupted. Hence only a part of the hold is able to close radially and tangentially over the teeth and the inner rotor body. so that the oscillation is weakened. placing): in the rotor slots windings or copper hers (Z, as shown by hatching. which m r he conmaimer.

nected to each other in any suitahl the field in the hody of the rotor is practically neutralized by the currents induced in the copper, so that apart lrom .lQZtl2.tS only the part of the field over the laces of the teeth is effective.

The details of design may vary considerahly. The number of the rotor conductors "may be greater or less than the nnrnl er of:

stator divisions. or equal thereto providing that the sizes of the div.'sions are di'llierent, so that they act successively under dill crent positions of the imluctors in relation to the poles. The divisions of the stator or rotor may also vary amongst themselves. By this means other new eilfects may he ohtained as hereinafter mentioned more in detail in con nection with the description of the other figures.

"In Figure 2 for instance the stator has divisions of: two sizes in the proportion of l :2, and the rotor has a division equal to the hirger stator division, and, twice the sine ol: the small stator division. In the position shown the flux circuit. oil? pole 4: is closed over 7), I), and the two adjacent poles 5 and whilst the iluz; circuits of poles 2 and (3 are open. The opp site conditions obtain in the position removed by oi the rotor pitch ;"ro1n that oi 2.

in Figure the magnetic bridging is produced by separately inserti 1.1g bridge pieces (7. c as shown on the right hand. side. in ii the rotor liody may con- 11s case the rest or sistof electrically conductire metals as shown by hatching. The same counter anipere turns as in a short-clrcuitcd \wndin will thus he produced in the solid metals and will. serve on the one hand to annul. the rotor dispersion.

l'li the inductive winding a-c is only placed on the poles .2 4-, 6 etc. and wound in opposite directions on adjacent poles. the induced currents or elcctromotive forces are added to each other. This is owing: to the :Eact that the flux in a pole such 2 hegg'ius s'jo increas-Je as the flux in a. pole such fl; hegins to decrease. The windings must couscquently he in different directions in order that the electronmtive liorccs may add. For the purpose of producing excitation the 1nachine must he provided with another which ng, the coils of which are so arranged that l. 3. 5. T for instance hccon'ie N poles and 53. t. 6, S poles. The flux in the excited poles l. 3. 5 and T is constant in direction and also in quantity since the flux from any pole of this set is able to switch from an induccd pole on one side to an induced pole on the other at the time the flux in the first iruluced pole begins to decrease. Tu this exciting winding. consequently. no tension will he induced and it is unnecessary. as is the case with other machines ha vino a variable field in the excited poles. to arrang a chokingcoil in. front of the exciting circuit. ln poles 41-. (5. etc.. oscillations occur. first to one sidev and then to the other. ln the poles '1. ll, 5. 7, there are no oscillatixms at all when using continuous current for excitation and any induced tension can he removed from the exciting circuit by only ush'u'z' these poles lor the purpose of exciting rud placing;- the ex iting winding; c c only on alter] e poles.

This :u'rangyeiueut may he of practical value it the machine is excited with contiul'un s current at '100 to 200 volts. which may involve a 't'airly high numher of turns per pole and consequently high tensions at the exciting terminals. The constant field in the exciting poles l, 3, 5, 7 has the adrantaae that these poles are highly saturated and may consequently have a small cross section, shown in Figure 2.

In Figure 2 the segments 0 c are inserted,

the rest of the rotor being made in the form of a solid steel bronze wheel, rendering it simple and strong.

In Figure 3 the number of rotor divisions is equal to the number of stator divisions, the stator has divisions of two sizes, alternating with each other and in the proportion of 1:3, and the rotor has a division equal to of the larger stator division, that is to say, twice the size of the smaller stator division. In the position shown, the flux circuit of pole 2, for instance, is closed over the pole 3 to the right, and in the position removed by of the rotor pitch it is closed over the pole 1 on the left.

If the inductive winding a-a is again placed for instance only onthe poles 2, a, 6, etc and the exciting winding ee on the poles 1, 3, 5, etc., in such manner that 1, 5, 9, etc, are N poles, and 3, 7, 11, etc., S poles, then the inducedpoles 2, a, 6 will form alternating poles. For instance, poles 2, 6, 10, etc, will be N poles in the position shown, and in the next position S poles; poles 4t, 8, 12, etc., will in the position shown be S poles, and in the next position N poles.

The result is that the induced field in the induction coils of thewinding a does not only pulsate but becomes a pure alternating field, and for producing an equal E. M. F. the amplitude of the field oscillation may be reduced to less than half.

For the purpose of wireless telephony or signalling by influencing the exciting circuit, this construction has the advantage that owing to a weaker field being allowable the exciting winding also has a small selfinduction and is therefore'more easily influenced.

In Figure 4; the number of rotor divisions is the number of stator divisions. In the position shown the flux circuit of pole 2 is closed over the pole '1 on the left, and in the next position, removed by l;- of a rotor division, theflux circuit is closed over the pole 3 on the right.

In this case again the winding may be divided into two parts, and one part or both may be used for exciting. With similar connections, the conditions are in principle analogous in Figure 4 and Figure 3. The only difference is that owing to the smaller number of rotor divisions, with equal excitation, the field per pole is proportionally larger, and th frequency produced is propo rtionally less. a

The method can be used for producing high or normal frequencies, and in generators as well as in motors, i. e. for converting mechanical energy into electrical energy and vice versa. The rotor may of course be used as the magnet system, and the stator as the armature.

The excitation may be produced by coniments, each of said se tinuous current or by alternating current,

or by a pulsating current, for instance for the purpose of wireless telephony.

Finally, known means such as condensers arranged in parallel or in series with the outer circuit, may be used for increasing the oscillation or for other purposes. By this means the fall of pressure occurring with load may be compensated in a particularly simple manner, as the rotor dispersion can be kept at a minimum, and appreciable dispersion only occurs in respect of the stator windings between the pole tips, and the reaction thereof on the pressure can be reduced, to the limit of saturation of the iron, by a condenser of suitable proportions connected in series.

Having now particularly described and ascertained the nature of my said invention and in what manner the same is to be performed, I declare that what I claim is 1- 1. An electrical machine comprising in combination a relatively movable field and armature, said field having a plurality of poles, and said armature having its iron surface in the form of segments, said segments being adapted to individually and successively magnetically bridge the pole tips of opposite polarity, and means forming a short circuit around each of said segments.

2. An electrical machine comprising in combination a pole system and an armature system, said armature system presenting a surface in. the form of a plurality of segents being adapted to successively magnetically bridge the pole tips of opposite polarity when the centre of the surface of the individual segment is midway between the poles which are bridged thereby, and means forming a short circuit around each of said segments. 3, An electrical apparatus comprising in combination a pole system and an armature system, said armature system presenting a surface in the form of a plurality of segments, and connected conducting metal intermediate said segments, said segments being adapted individually to magnetically bridge the pole tips of opposite polarity.

4. An electrical apparatus comprising in combination a pole system, and an armature system consistmg of suitable magnetic pleces, sald pieces belng surrounded by connected electrically conducting metal and being adapted individually to bridge the pole tips of opposite polarity.

In testimony whereof I have hereunto set my hand in presence of two subscribing witnesses.

ALEXANDER HEYLAND.

Witnesses:

CHAS. ROY NASMITH, K. J ZACARY. 

